Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
343 AM EST Sun Nov 20 2022

Valid 12Z Sun Nov 20 2022 - 12Z Wed Nov 23 2022

...Great Lakes...
Day 1...

A surface ridge axis currently approaching Duluth will shift east
across the Great Lakes through tonight. Lake effect snow will
taper off around the time of the passage. Until then, westerly
flow will promote multi-band streamers off Lakes Superior/Michigan
and quasi-single bands off Lakes Erie/Ontario. The Erie/Ontario
bands have shifted south with the cold frontal passage where they
will persist until this evening (Erie)/overnight (Ontario). There
is a risk for an additional 6" off the southeast shore of Erie
(beginning after 12Z). A potent Lake Ontario band currently over
the Tug Hill Plateau will continue to shift south to the
southeastern shore/western Mohawk Valley where there is a risk for
2' of snow through tonight.  wider expanse of snow to the
southeast of Lake Erie but still a rather focused area east of
Lake Ontario where more than 18" is still possible.

...Washington...
Day 3...
A shortwave trough pushes into the central BC coast Tuesday with a
notable plume of Pacific moisture directed to Washington with
moderate to locally heave precipitation. Snow levels are generally
5000-6000ft by late Tuesday with moderately high Day 3
probabilities for 6 or more inches for the north WA Cascades.


The probability of significant icing greater than 0.25" is less
than 10 percent.

Jackson